Chicken Florentine

Gather the ingredients.

Mix together 1/4 cup all-purpose flour, 1 teaspoon fine salt, and 1 teaspoon ground black pepper in a shallow dish.

Place 2 large boneless, skinless chicken breasts (about 1 pound 6 ounces total) on a clean cutting board and use a sharp knife to cut each breast in half horizontally through the side of the chicken, using a gentle sawing motion, to make 4 equal (1/2-inch thick) chicken cutlets.

Place each cutlet in the flour mixture and turn a couple of times to coat well. Shake off any excess flour.

Heat 3 tablespoons olive oil in a large high-sided skillet over medium-high heat. Add the chicken to the oil (in batches, if necessary, to avoid overcrowding the pan). Cook until golden brown on the first side, 2 to 3 minutes.

Flip the chicken cutlets and cook until the chicken releases easily from the pan (browning is not important), about 1 more minute. Transfer the chicken to a large plate and set aside while preparing the sauce (the chicken will not be cooked through). Do not wipe the skillet clean.

Add 2 tablespoons unsalted butter and 2 medium shallots, finely chopped (about 1/2 cup) to the pan and cook over medium, scraping up any browned bits from the bottom of the pan and stirring often, until the shallot has softened, 1 to 2 minutes.

Add 5 medium cloves garlic, finely chopped and cook, stirring constantly, until golden brown and fragrant, about 1 minute.

Add 1 cup dry white wine and bring to a boil over medium-high. Cook, stirring occasionally and scraping up all the browned bits, until almost completely reduced but the pan still appears saucy, about 4 minutes.

Add 2 teaspoons Dijon mustard, the remaining 1/2 teaspoon fine salt, the remaining 1/2 teaspoon ground black pepper, and 3/4 cup heavy cream and stir to combine. Bring back to a simmer over medium heat. Cook until slightly thickened, about 2 minutes.

Add 3 cups lightly packed baby spinach and stir until starting to wilt, about 1 minute.

Add the chicken, browned-side up, back into the skillet along with any juices from the plate, and continue to cook over medium heat until the sauce has thickened slightly more and an instant-read thermometer inserted into thickest part of the chicken registers 160 F, about 3 minutes.

Using a Microplane or rasp grater, grate Parmigiano-Reggiano cheese to taste directly over the chicken. Sprinkle with 1 tablespoon finely chopped parsley, if using, and serve immediately.